“I told Jay Roach, who directed and did a beautiful job, ‘Let me go out on this limb and go out there, because I don’t know how far out I should go,'” the Emmy-winning actor said in an interview for the Actors/Directors/Writers issue of TheWrap Magazine. “If you start to hear the limb cracking, just bring me back.”

Cranston’s source material ranged from audio and video tapes of Trumbo to conversations with Trumbo’s daughters — where he learned about some of his character’s personality quirks.

“The daughters were incredibly helpful, as was his daughter-in-law, Nancy Escher, who was married to Chris Trumbo, who has passed away five, six years ago,” said Cranston, who just earned Golden Globe and SAG Award nominations for his performance. “They very lovingly said, ‘There are times when I’m looking up at the screen and see my dad. That’s him.'”

The movie is important for Cranston, as it delivers an important message about an event in which many were stripped of their civil liberties. “Trumbo” follows the Hollywood 10 as they were blacklisted in the industry in the ’40s and ’50s for their membership in the Communist party. To find work, Trumbo used an alias and wrote screenplays for big studios like “Roman Holiday” and “Spartacus.”

“Civil liberties were in jeopardy of being lost,” Cranston said. “In fact, they were. And these men went to prison for committing no crime, just not cooperating with this overreaching branch of government. Then they were stripped of their ability to earn a living in their chosen field, to be responsible for their families. They lost homes, families broke up, marriages split apart, there were some suicides. It was an ugly thing.”